Nomikou Maria, Janssen Arne, Sabelis Maurice W
IBED, Population Biology, University of Amsterdam, PO Box 94084, 1090 GB Amsterdam, The Netherlands.
Exp Appl Acarol. 2003;31(1-2):27-36. doi: 10.1023/b:appa.0000005150.33813.04.
Predatory mites of the family Phytoseiidae feed on herbivorous mites and insects but they also use a variety of non-prey food items, such as pollen and nectar. Plant tissue is another potential food source. We investigated whether plant feeding occurs in the two phytoseiids Euseius scutalis (Athias-Henriot) and Typhlodromips swirskii (Athias-Henriot), which are natural enemies of whiteflies. These predatory mites can suppress populations of Bemisia tabaci (Gennadius) on isolated plants and are candidates for biological control of this pest. Both species can be reared on a diet of pollen, but E. scutalis requires a leaf tissue substrate, suggesting that this species might feed on plant tissue. To test this hypothesis, we applied a systemic insecticide (aldicarb) to cucumber plants and assessed the survival of predatory mites on leaves from insecticide-treated plants and untreated plants, both in presence and absence of pollen. The survival of T. swirskii was not affected by the presence of systemic insecticide in the plant. However, the survival of E. scutalis on leaves from insecticide-treated plants was 10 times lower than on leaves from untreated plants. Since the two species showed similar sensitivity to the insecticide when applied in a slide-dip test, this suggests that E. scutalis ingested insecticide through feeding on the leaf tissue. Mortality on treated leaves was observed both in absence and presence of pollen, suggesting that plant feeding is indispensable for E. scutalis. The extent to which plants are used as food by E. scutalis requires further analysis.
植绥螨科的捕食性螨类以植食性螨类和昆虫为食，但它们也会利用各种非猎物食物，如花粉和花蜜。植物组织是另一种潜在的食物来源。我们研究了作为粉虱天敌的两种植绥螨，即盾盘大绥螨（Athias-Henriot）和斯氏钝绥螨（Athias-Henriot）是否会取食植物。这些捕食性螨类能够抑制隔离植株上烟粉虱（Gennadius）的种群数量，是这种害虫生物防治的候选物种。这两个物种都可以用花粉饲养，但盾盘大绥螨需要叶片组织基质，这表明该物种可能会取食植物组织。为了验证这一假设，我们给黄瓜植株施用了一种内吸性杀虫剂（涕灭威），并评估了在有花粉和无花粉的情况下，捕食性螨类在经杀虫剂处理的植株叶片和未处理的植株叶片上的存活率。植株中内吸性杀虫剂的存在对斯氏钝绥螨的存活率没有影响。然而，盾盘大绥螨在经杀虫剂处理的植株叶片上的存活率比在未处理的植株叶片上低10倍。由于在玻片浸渍试验中这两个物种对杀虫剂表现出相似的敏感性，这表明盾盘大绥螨是通过取食叶片组织摄入了杀虫剂。在有花粉和无花粉的情况下，处理过的叶片上都观察到了死亡情况，这表明取食植物对盾盘大绥螨来说是必不可少的。盾盘大绥螨将植物用作食物的程度需要进一步分析。
